Depth of dip control apparatus



May 16, 1950 R. A. TARLTON 2,508,200

DEPTH 0F' DIP CONTROL APPARATUS Filed, Nov. 2l, 1947 2 Sheets-Sheet 1 F1' .1. F j P a) g e a4 J ,5 38 4 32 WITNESSES: INVENTOR Buffe/b4. a'r/an.

P Y n BY ATTORNEY May 16, 1950 R. A. TARLTON 2,508,200

DEPTH 0F DIP CONTROL APPARATUS Filed Nov. 2l, 1947 2 Sheets-Sheet 2 wlTNEssEs: Q INVENToR ATTORNEY Patented May 16, 1950 2,508,200 a DEPTH OF DIP CONTROL APPARATUS l vRussell Tarlton, Kenton, Ohio, assigner to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 21, 1947, Seal No. 787,421

13 Claims.

This invention relates to apparatus for immersing articles in a liquid and, more particularly, to apparatus for controlling the depth to which articles are immersed in a liquid in such manner that the immersion is regulated in accordance with the size of the article and articles of various sizes are immersed to the same depth.

More specifically, this invention relates to apparatus for immersing electrical structures, such as the stator structures employed in electric motors, in a bath of insulating varnish to impregnate the electrical windings on such structures with varnish and to provide the entire structure with a coating of insulating varnish. Certain features of the apparatus disclosed in this application are covered in the copending application of R. L. Ruleff and R. A. Tarlton,

`Serial No. 787,422, filed November 21, 1947 and to which reference is hereby made.

Many electrical articles, such as stator structures, comprise a magnetizable supporting member on which a coil of wire is wound as an electricalenergizing winding. The coil or energizing Winding is provided with flexible insulated leads by which an electrical connection tothe winding may be made. According to the above-mentioned copending application, such structures are',vr placed on supports carried by a conveyor chain and impregnated and -coated with varnish by immersion or dipping in a bath of insulatingvarnish. The dipping of the articles is accomplished in a continuous manner as they are carried past the varnish dipping station by the conveyor chain. Thev immersion may be accomplished by moving the article into the dip tank or by moving the dip tank with respect to the article, the latter being the preferred method.

Although it is necessary that the electrical structure be impregnated and coated with varnish, the application of a coating of varnish to the flexible leads is to be avoided. Such a coating causes the leads to become brittle and subject to damage by bending. In order to prevent coating of the flexible leads with varnish, one of the principal objects of this invention is to provide apparatus by which the depth to which the electrical articles are immersed in varnish is controlled so that as little as possible of the leads are immersed. To this end', there is provided a hydraulic motor for moving a varnish containing dip tank toward and away from the article to effect its immersion in and withdrawal fromA the varnish. A photoelectric cell and timing device so regulates the operation of the hydraulic motor that the article is immersed to a predetermined depth below the level of the varnish in the dip tank. In this manner, all of the article is immersed and only a short length of the exible lead is coated with varnish. In addition, the control of dipping is accomplished in such manner that articles of different sizes may be fed successively to the dipping station and cornpensation for the varying article sizes will be made automatically.

A further object of this invention is to provide a liquid containing tank with a liquid recirculating system by which the level of liquid in the tank is maintained together with apparatus for r controlling the depth to which an articlefis immersed in the tank.

Another object of the invention is to provide f a novel arrangement of apparatus for moving -a 1 receptacle containing liquid toward and away from a supporting member to immerse articles carried by the supporting member.

i an article and dip tank as a dipping operation is being performed which is effective to measure the size of the article and initiate control mechanism for stopping the relative movement at a predetermined point, the point of stopping being thus varied automatically with the size of the article.

Other objects and advantages will become apparent from the following description:

In the drawings, there is shown a preferred embodiment of the invention. In this showing:

Figure 1 is an elevational view of a dipping station for immersing articles carried thereto by a conveyor chain; Y

Fig. 2 is an enlarged side view of a portion of the apparatus shown in Figure l, taken from the right of Figure l, and particularly illustrating the arrangement of the liquid containing receptacle and elevating mechanism therefor;

Fig. 3 is a top plan view of the apparatus shown in Figure 1; and

Fig. 4 is a diagrammatic sketch of a control vsystem employed in connection with the apparatus shown in Figure 1.

Referring to Figure 1 there is shown a monorail conveyor chain I mounted for movement 0n a rail 2 by rollers 3. The conveyor chain is provided with supports 4 for articles 5 at equally spaced intervals thereon. 'I'he particular form of articles 5 shown in the drawings for which the system of this invention has been specifically deyised are stators for electric motors and com- Y turned by gravity to the reservoir 23.

ticular system illustrated is forT the. purpose. of,

impregnating and coating electrical articles,

such as stator windings, with varnishandzirr such:A

system the liquid contained?irIY-thetank-Eillis an insulating varnish. switch 2I is shown as beingvoperatedmby the rollers 3 `which support the conveyor chain I.

When the conveyor chain is stopped by-ftheflim-it switch 2l, mechanismf-is operated to raise the taule-.20 '-vertically,v asrviewedfrin Fig Lito a-eposition liniwhich :the-:articles or -stators i5,y which have stoppedin `an operativerdippingpositionawithrespectsto the tank2, areimmersedin the varnish containedinethetanlctif.y The stators-'areimmersed in :.thervarnis-h for afpredeterrnined period off-time'atenwhichthe-tank 2li isrloweredtothe position@showninfFig;Y 1ra-nd the conveyor: chain In the drawingsthelimit' port 36 at the bottom thereof for connection to the flexible exhaust conduit 26. The central varnish containing chamber 33 is provided with a port Si at the bottom thereof for connection to I is then started again to move-thernextsupport i hands statory carriect therelcyfintc` an opera-tive iso dippngpositon and sto vmovefthe supportIv licarg ryingf the:statorsfwhichhave? just been dipped to afidraining:.positionvabovewa drainpan22' which a.; collectsnf thefvarnishdripping; from.' the" stators 5 These operations are carriedzoutiilnfa ccntinuous 35 step-by ystep or` lintermittent .manner andfrequire aepredeterminedf: amount of time between. intermittentoperations orfthe cha-in- I The tir-.nereqnired bythe:dipping-operations-lprovides afcontrol feature whichfis covered.l and. completely sety forth.-i-Ir the-copending` application7 mentioned above.

Varnish iscontinuously-"circulated `through l the dipftank Zffrorn ra-.freservoir-:'23rby af pump-"2 d which@ operatesstefdeliver varnishte thetank 2 Il i through a-r- -eXible--supply conduit'- y2 5 Overflow chambersatfthefendsfof the dip tankfnZ iare-comA Imctedfw-ithA flexible exhaust conduits-to a V'main return conduit 2-'fiby -whichfexcess--vvarnish is're 'llheed-rip` panwZ, asshownlirrfFig. l; is also-connected to the return''conduit- Z'If'so'that varnish dripping 'frornfrthe stators-S is alsoreturnedvto the reservoirzfZSe Water cooled-rheatexchangers-1Eil-are ni-'ov-ided.1 on Vfthe suppl-y'andev exhaust' conduits 25,.

Y'llhesdip' tank/Zrhasfrits-oppositeends 3 If and-- 32 angularly offset from eachother *inf order toV accommodate thefar-rgularr inclination-Lof the arms 29;? fands the@ stator-'s- 5 carried Y- thereby.. In "this nishf to: :immersethei'stators" 5^ mountedk oni the ammsZBr A-A centralfchamberf orthedip 'ta'nkfil is separated :from overow': compartments- 341 `at eac'lif.en'dirthereof` by-foverwfweirs' 35.-A Each* of Y tneacompartmentsisprovidedswith anzexhaust the flexible inlet conduit 25.

The arrangement of the overflow chambers 34 and weirs 35 together with the varnish recirculating-system provides a 'very important feature with respect to'regulating the depth to ywhich the stators 5 are immersed. By this arrangement, varnish is continuously supplied to the chamber 33.and overilows -into the compartment 34. The surface level of'varnish in the chamber 33 is thuszmaintainedconstant. The overflow feature -inadditionlitak'es care of that varnish displaced by-*the'stators 5 vupon immersion and it will thus be noted-that such immersion does not alter the level of varnish in the chamber 33. The surface level of the varnish is determined solely by the upper edges of the weirs 35.

Verticalmovement cfszthe:varnis-hf.tank 20 is guidedffby'fchannel members 35 which'have. slid'- ingengagement' with the-'corners ofthe dip ytank 25; Vertical' movement: effnthe` dip'ftankf 20' is leffected by a hydraulic-cylinder 35' having a piston (not shown) thereinY connected -to a. rod lil-on the upper end roiY which ismountedf the dip tank 25.' Conduits'i andfilareconnected toopposite ends ofthe-hydraulic cylinder' Blrand Vare alternately connectedwith lailuid.fsupply'conduitslifl and exhaustrconduit sY-bymeansofareversing .valve indicated'as a wholeby the numeral e5; as shown in Fig. 4. A w'tregulatingfvalve 5i-is mounted inthe conduit iZforfcontrolling `the:V downward movement? ofk the'tank 26.' in a manner: to be described: The uid4 supply conduit` 43 is. connected'toV a suitable source- (not shown) for' deliveringA hydraulic fluid under pressure thereto;`

A source of-v lightVv 49I and a photoelectri'c cell 5I)y arermounted on thetank 20; asv shown in` Fig. 2, for controllingth'e" extent of kupwardmovement of theetank Ztin a manner tobe'described. A' plate 5I' isv connected'tooney of the guiding supportsrsandiis positioned -betweenI the light sourceffand photoelectriccell 59A when the tank Zli'isV in itslowerm'ost" position;` The'plat''5l is so" arrangedthat' the photoelectric cellv 5l! -will be energizediby the light sourcef49' immediately upon'clearing the upper edge 52er the plate 5I, if no' statorsf are'on the support :4 when theftank 20 isfelevated'. Iii a statorv 5 is` carriedby the support 4', such stator will beeiiectiveto maintain the photoe'lectric cell' 5U' deenergized until thel tank '20"' has moved the' lghtsource 49= "suiciently'iar'toclear'theupper edge ofthe stator 5. At' that` time, the ph'otoelec'tric cell will be energi'zecl4 to` effecta control" functionA inta manner to be described.'

In' Fig'ill the'ess'ential parte' ofthe apparatus heretofore described' which are .necessary to an understanding of the control system have" been indicated' diagrammatically and* like numerals have been' applied to similar parts. In this showing the reversing valve 45" comprisesV ak casing 53 havingfa pairfof` valve structures 54 and 55 mounted therein andrespectively provided with a.' spring biasby springs 5B toa closed position. Solenoids 5'! and 58'are providedfor operating thevalvestructures 54 and 55L against' theV bias provided by" the springs'f Upon energization of'the solenoid 5'! A`the valve.'structurer 54fwill' operate toconnect the conduit 52 with the uid pressure supply conduit 43"and to connectI the conduit A4 I with the Aexhaust conduit 44. This .action positions.

will admit fluid under pressure to the lower end of the cylinder 39 and exhaust uid from the upper end of the cylinder 39 to thereby move the `tank 2liV in an upward direction. Upon deenergization of the up solenoid 51 and energization of the down solenoid 58, the valve structure 55 will be operated to reverse the pressure connections of the conduits 4I and 42 to effect downward movement of the varnish containing dip tank 20.

' The speed of movement of the tank 20 is controlled by the now regulating valvef46 as mentioned above. rlhe ow regulating valve 46 comprises a casing 59 containing an adjustable ballcheck valve 50 and a flapper valve 6l, both of which are provided with spring biases to closed Upon connection of the conduit 42 with the source of fluid pressure supply, such pressure will be effective to maintain the ballcheck valve 69 closed and to open the liapper valve 6l to thereby provide a substantially direct connection of the lower end oi the hydraulic cylinder 39 with the supply conduit 43 and the hydraulic cylinder 39 will operate to move the 'dip tank 20 upwardly at a maximum speed determined by the pressure of the fluid in the Supply conduit 43. Upon connection of the conduit 42 with the exhaust conduit 44 in the lowering 4movement of the dip tank 20,/the fluid leaving 'the lower end of the cylinder 39 will operate to close'the flapper valve 6l and unseat the ballcheck valve 69. The ball-check valve 66 provides a restricted connection between the separate parts of the conduit 42 and thereby limits the escape of fluid from `the lower end of the cylinder 39 and the downward speed of the dip tank 20. Downward speed of the dip tank 26 may be regulated by operation of an adjusting member '62 to vary the tension of a spring 63 which provides a closing bias for the ball-check valve 6D. By adjusting the tension of the spring 63, the pressure required to unseat the ball-check valve 60 will be varied and the rate of flow of fluid through the conduit 42 may be regulated. It `will be understood that the showing of the reversing valve 45 and flow regulating valve 4E is `diagrammatic for the purposes of this description and that the particular structure shown forms no part per se of this invention. Accordingly, it will be understood that any conventional valve structures may be employed in place of the valves 45 and 46 without departing from the principles of this inventionv vThe control system illustrated in Fig. 4 is energized from a pair of alternating-current supi ply buses 64 and 65 and employs a master timing circuit TM, a dip timing control circuit TD, and an over-travel timing circuit TO which are energized by the supply buses 64 and 65. The timing control devices TO. TD and TM are provided, respectively, with starting relays 66, 61, and 68 and with operating relays 69, 19 and 1l. -The timing relays are identical in construction and like numerals have been employed to designate like parts thereof. Each of the relays is provided with a vacuum tube 12 having a condenser 13 in its plate circuit, a pair of resistors 14 and 15, and a potentiometer 16 having vaslide contact 11 connected in series with the grid of the tube 'i2 through a timing condenser 89 which has a discharge resistor 18 connected across its terminals. Since the operation of the timing control relays is the same, it will only be necessary to describe the operation of one of the relays lforthepurpose of this description. .Referring 6 to the over-travel timing relay TO,` it will be noted that the cathode of the tube 12 is connected to one of the A. C. buses 64 through the resistor 15 when its starting relay 66 is open. Under this condition, the condenser 80 will charge with the polarity shown, by means of the grid current, to the peak of the voltage between the bus 64 and the slider 11 of the potentiometer 16. When the start relay 66 is energized, contacts 19 will close to connect the cathode of the tube 12 to the other A. C. bus 95. The grid voltage then consists of two parts; namely, the A. C. voltage between the other of the buses and the slider 11 of the potentiometer 16, and the D. C. voltage across the condenser 80. Since the D. C. voltage in the grid circuit, by reason of the charge on the condenser 30, is greater than the A. C. voltage, the tube 12 will not pass current. The D. C. voltage, however, immediately starts to decrease because condenser 8l) discharges through resistor 18 and after a predetermined time the tube 12 will pass sufficient current to energize the operating relay 69. The length of time between the energization of the starting relay and the energization of the operating relay of any of the timing circuits TO, TD, or TM can be adjusted by their respective potentiometers 16. The condenser 13 supplies current to the coil of the operating relays on the half cycles when the tubes 12 are not passing current. The starting relays must remain energized for the duration of the time delay to effect operation of the operation relays. Deenergization of the starting relays will cause the operating relays to be deenergized and will reset the timing function or control by recharging the condenser 80. Each of the timing control devices TO, TD and TM is provided with starting contacts 19 under the control of the starting relays 66, 51 and 68, respectively. The operating relay 69 is provided with contacts 9| and 82 and the operating relays 10 and 1l are provided with contacts 83 and 84 respectively. The showing of the timing control devices TM, TD and TO is diagrammatic and it will be understood that any other suitable type of timing device may be employed without departing from the principles of this invention.

The timing control devices TM, TD and TO operate in connection with a plurality of control relays RI, R2, R3, R4, and R5. Control relay Rl controls contacts and 86; control relay R2 controls contacts 81 and 88; control relay R3 controls contacts 89 and 99; control relay R4 controls a contact 9|; and control relay R5 controls contacts 92 and 93. Limit switch 2l controls contacts 2IA and 2|B and is provided with the spring 94 for biasing it to a position maintaining contact ZIA closed.

vThe conveyor chain l is driven by gearing 95 operated by an electric motor 96 which is energized from the alternating-current supply buses 64 and 65. The motor 99 is provided with a solenoid operated brake 91 having a spring 98 for biasing it to an operative braking position whenever its operating coil 99 is deenergized.

In the operation of the control scheme shown in Fig. 5, limit switch contact 21A will be closed when the conveyor chain is being driven from the motor 96 through the gearing 95. With the limit switch 2 IA closed, relay RI will be energized and contact 85 will be closed, completing a circuit to the motor 96 and to the operating coil 99 of the solenoid brake 91 to thereby maintain the brake in inoperative position against the bias provided by thespring Y98. Upon movement of one of the 'supports-fd into 1an: operative. clipping position with respect.- tothe dip. tank210, one of the rollers .3i 'wilicperaiteV the limit :switch .2| `against its bias provided by thespringd 'to :open the contact 2 |AV andi fclose: tlieacontac-ti 2 IB. Opening of. `contact 21A will deenergize relay Ril to open contact 85 and close contact 86. Opening of "contact 85 `will deenergizethe:motor 98- and operate the brake 91 by deenergizingitsfoperat'ing coil 99. The `conveyorzchain will vthusstop: in the position shown in. Fig'. 5Y with one. of the supports 4" carrying :stators in an'operzat'rve dipping position with respect, to the dip tank 20.1; A single-.po'lef'doublethrow A'switch I 00 is providedffor 4energizing Ythe relayfllv toeffect operation of the conveyor chain .icontinuously and' without its operation being subject'S-to operation of `the limit switch 2t.

Whenfflim'it switch 2! operates toY open contact'. 21A Vto stopf movement cf the conveyor chain 1, .it also operates to closeY limit switch contact lZIB. Closure of limitswitch 21B" energizesl starting relay 88 to start' the timingV operation ofthe 'master timer TM; Afterv a predetermined time, relay ll ofthe timer TM" will operate to close contact B4 for a purpose to be Adescribed'. At the same time relay 88 Visl energized, relay Ril 'is energized to close contact 9|.

It will be'` recalled that contact 'BE closed when relay R|` was deenergized. Closure of contact 86 completes a circuit for energizing the up contro'l'valve'solenoid `5f|"through the normally closed contact-82, of the-timer TO, normally closed contact 88 of relay R2',- closed contact 86V of relay Ril, and'v the switch |00. Energization ofthe solenoid SToperates the valve structure 54 to admit uid under pressure to the lower end of the hydraulic cylinder 39"*0 raise the dip tan-k 20 asV described above. As the dip tank 20 is elevated', it carries with it the light source 49 andl photoelectric tube 50 as described above. When the light -source 20 is raised to a position above the stator 5, the photocell 50 will be energized `to apply ka positive lbiasfto the gridV of a control tube |02. The tube |02 will then be rendered conductive and will energize a relay |03 to close contact |04. 'Closure of' contact |04 enerH gizesrelay R5 to close contacts 92 and 93; Closure of contact 92 vsets up a holding circuit'for relay R5. Closure` of contact 93 energizes the `start relay 66 to'clse contact 19 of the overtravel timer TO. After a predetermined time, the condenser will be discharged to renderthe tube 12 conductive and to thereby energize cperating relay,r 69 `to open contact 82 and close contact 9|. Opening of contact 82 will deenergize the ,up control solenoid 5`|Yto permitl closureof the valve structure 54 by the bias of its spring 56 and the supply of fluid pressure will be cut 01TY from the hydraulic cylinder 30 and the upward movement of the dip tank 20 will be stopped.

It will thus be noted that the stopping of the lupward movement of the tankV 20 Vis dependent upon operation of theover-travel timing relay TO completing its vtiming operation and operation of relay t9. It will also be recalled that the timing'y function of the relay TO is initiated by energization of the photoelectric tube 5G. The time delaybetweenV the energizationv of the iphoto electricV tubef50 and the operation of the re- W lay 89 to stop the'upward movementY of the tank 20' is so adjusted :by the regulation ofthe po'- sition oithe slidecontact that the tank 20 will travel a predetermined distance .after r'its up- -per edge clears theupper edge: of. the winding -gization of relay R2.

5;r This predetermined Adistanceis. such thatthe winding 5-will be immersed in the` varnish contained in the tank 20V to a predetermined depth which is suiiicient toimmerse the exiblelead 1 to a depth. .of about. 1 inch. It will thus :be seen that the upward movement of the tank 20 is stopped at a predetermined point with respect to the length Vof the flexible lead 1 immersed in the Varnish irrespective of the size of Vthe stator 5 being dipped.

When operating relay 89 of the overetravel timing relay TO operates to open contact 82 and stop. the upward movement of the dip tank 20, contact 8i closes to energize start relay 81 of the dip timer relay TD. After a predetermined time in whichA the stator 5 is maintained immersed, operating relay 10 is energized to close contact 83. Closure of contact 83 completes a circuit to energize down solenoid valve58 :through contact 83, contact 88 and switch |00.. Energization of solenoid 58 moves the valve structure 55 against the bias of its spring 56.130 ad.- mit pressure to. the upper end of the cylinder 38'. through the conduit d! and to exhaust `fluid from the lower end of the cylinder 39 through the conduit 42. The rate of flow of the exhaust fluid through the conduit 42 is controlled bythe Valve structure 48 to thereby control the speed at which the tank 20 is lowered, as explained above. The regulation of the lowering speed and its purpose is completely described and covered in the copending application mentioned above.

Upon closure of contact 83 to energize the down valve operating solenoid 58, control relay R2 is energized by a circuit through contact 83, contact 86 and switch |00. Energization of relay RZ closes contact 81 and opens contact 88. Closure of` contact 8l sets up a holding circuit for the relay R2 through contact 87, jumper lead and contact'S'l. Opening of contact 88 interrupts the holding circuit for Yrelay R5 through contact 92' and relayV R5 is deenergized, and contacts 92 and 93 open. Opening of contact 93 deenergizes starting relay 68 of the overtravel timer TO and relay 69 is thereby deenergized to open contact 8| and close contact 82. Closing of contact 82 does not energize the up valve solenoid 5! at this time by reason of its energizing circuit beingy open at contact 88. Opening of contact 8|` by deenergization .of the operating relay 69 of the over-travel timerTO opens the energizing circuit of starting relay 81 of the dip-time control TD and its operating relay 10' is deenergized to open contact 83; vOpening of contact 83 does not deenergize the Vdown control valve due to a holding circuit vtherefor through contact 8l which was closed upon ener- It will thus be seen that opening of contact 88 is effective to deenergize starting relays 8E and 81 to thereby reset the timing control devices TO and TD for subsequent cycle of operations.

As lowering movement of the tank 2811s corrtinued by reason ofthe energization of the kdown valve operating solenoid 58, the stator 5 immerges from the top` of the tank 20 and moves between the source of light 48 and the Iphotoelectric tube 50. The tube 50 will then cease to conduct current and relay |83 will be deenergized to open contact |04. Y

As the tank 20 approaches its lower position, an. operating lever M5 will strike a limit switch |06 to close contact |01. Limit switch' ,|05's pivotally mounted and Yis .providedwith a grav-- `ity bias to its open position. It is in :the path 01 movement df the operating member los carried by the tank 20 during both the up and down movements of the tank 20. The lever is connectedby a'pivot |08 to the tank 20 and is provided with a spring |09 biasing the member |05 to a position against stop pin ||0. In the upward movement of the lever |05, the spring |09 is compressed and the member |05 rides over the limit switch |06. In the down movement of the tank 20, pivotal movement of the oper- :ating member |05 is prevented by the stop pin ||01and` the member |05 will strike the limit switch |06 to effect closure of the contact |01.

Closure of contact |07 energizes relay R3 by completing a circuit through circuit 9|, the lead l I'I, and contact |01. Energization of' relay R3 closes contact 89 and contact 99. Closure of contact 89 completes a holding .circuit for the relay R3 through contact 89 and contact 9| of relayfR4.

Closure of contact 90 by energization of relay R3v is effective to set up an energizing circuit forfrelay RI to start up the conveyor system in .the event that the master timer TM has completed its timing operation and has operated to close contact 84. It will be recalled that the starting relay 68 of the timer TM was energized when limit switch 2| operated to close contact 21B to stop the conveyor and initiate the ele- The operations devation of the dip tank 20. scribed above in connection with the raising and lowering of the `dip tank 20 require a certain amount of time which is lemployed for the purpose of providing a control feature as explained and covered in the above-mentioned application.

.\ Upon completion of the operation of the timer TM and closure of both contacts 84 and 90, relay RI will .be energized to close'contact 85 and thereby energize the motor 96 to start the conveyor system. As movement of the chain is continued, the roller 3 will move from the limit switch 2| and its spring 94 will become effective -to open contact 2|B and V,close contact 2|A. `Closure of contact 2|Asets up a holding circuit forthe relay RI. Opening of contact ZIB deenergizes starting relay 69 of the overall timer TM so .that itsfcondenser 80 may be recharged for a subsequent timing operation. Deenergization of its starting relay 68 will result in deenergization of its operating relay ll toopen the contact `81s as explained above. Opening of contact 84 vwill not deenergize the relay Rl to stop the motor 96 because of the energizing circuit set up through contact 2IA, Opening of the limit switch contact 2|B also deenergizes relay R4 to open contact 9| and thereby deenergize relay R3 to open contacts 90 and 89. Opening of contact 9| byr deenergization of relay .R4 interrupts thelenergizing circuit for relay R2 to open contact 81 and close contact 88. Upon deenergiza- -tion of relays R2, R3 and R4, the control circuit is in condition for a subsequent cycle of operations as vdescribed above. y

. From the foregoing it will be noted that the manner in which the elevating movement of the -tank 20 is controlled to immerse Van article on `one of the supports 4 in varnish provides an effective arrangement by which articles of vari- =ous sizes maybe immersed to a predetermined fdepth in the liquid containedin a receptacle. Attention is particularly invited to the fact that the structure of the tank 20 and the recirculating ,System by which the varnish is maintained at a constant level is an important featurer in the .control of the depth to which the article is imy 10 mersed. Byraising the tank to a predetermined point with respect to the article, the article will be immersed to the point desired. It will also be noted that the photoelectric structure comi prisingthe photo-cell 50 and light source 49 in effect .measures the heighth of the article on the support during the elevation of the tank; During the raising movement, this photoelectric structure moves relatively with respect to lthe article 5 and is thus operative to initiate the stopping of the relative movement whenthe are ticle moves out of the range of the photoelectric structure. The point at which the photoelectricr structure operates will thus vary directly with the heighth oi the article. Since the movement after operation of the photoelectric structure as controlled by the timer TO is always constant, it will be seen that the movement may be made to stop with the upper edge of the article 5 a predetermined distance below the surface of the fluid in the tank 20. In this manner, immersion of stators in varnish in the tank 20 may be s0 conducted that only a short length of the ilexible leads will be immersed and the apparatus will automatically adjust itself for articles of different sizes.

In the above-described arrangement, the tank 20 and photo-cell 50 are elevated and lowered to eiect immersion of the stators 5. However, it is to be understood that the invention-.is equally applicable where the tankis stationary and the article is moved to eiect immersion. AIn Vsuch casethe article would still move relative to the tank 20 and the photo-cell 50, and the photo-cell y would be effective to measure' the heighth ofthe article being immersed.

Since certain changes may be made in the above construction and different embodiments ofthe invention may be made without departing from the spirit and scope thereof, it is intendedthat all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

VVl. Apparatus for immersing an article in a liquid comprising a tank containing liquid, a'support forthe article, power operated 'mechanism for eecting relative movement between said tank and said support in a iirst direction to immerse the article and in a second direction opposite to said rst direction to withdraw the article, circuit means controlled by said article and operable after relative displacement of said tank and said support through a distance in said first direction corresponding to the height of said artiole to produce an electrical output, and an electrical control responsive to said electrical output and rendered operative thereby for actuating said mechanism to stop said relative movement in said rst direction. Y .i

2. Apparatus for immersing an article in a liquid comprising a tank containing liquid, a sup.- port for the article, mechanism for moving said tank and support relative to each other in a direction to immerse the article in said liquid, a control device for operating said mechanism to stop said relative movement, and operating means for actuating said controldevice compris` ing a rst control and a second control, said first control being operative to actuate said second control upon movement of said article through `a distance varying with the height of the article on said support, said second control being operative to actuate said control device upon move- 151 ment of ysaidr article through a `distance, constitutingthe nnal portion of relative movement inf-said one direction which is independent of theheight ofthe article on said support.

3. Apparatus as claimed in `claim 2 wherein said first Vcontrolcomprises a light sensitive .devicewhich is maintained deenergized by said articleduring the initial portion vof its movement and -is energized to actuate said second control upon movement of said article out of range thereof, and said second control comprisesa timing-device which is rendered operative to actuate said -control device a predetermined time after actuation thereof'by--said rst control.

`4. Inwapparatus for immersing an article. in a liquid, the combination of a liquid receptacle havinga liquid -recirculating system for maintaining the liquid at a constant level in said receptacle, with a support for said article, means for moving said receptacle and support relative to=each other to immerse the article, a light sensitive device which is maintained deenergized by the Yarticle on said support during'the initial portion-of movement for `effecting immersion and Whichfisenergized by relative movement of the article out of range thereof, and a 4timing vdevice operated bysaid light sensitive device for stoppingI said relative Amovement a predetermined time after energization of said light sensitive device.

L5. In apparatus for immersing an article Vin a liquid-,the combination of a liquid receptacle having' a -liquid recirculating system for maintaining the liquid at aconstant level in said receptacle, with a support for said article, means for moving said receptacle and support relative toA each other to immerse the article, -a -light sensitive device which is energized in response to relative `*movement of said article with respect'thereto, and means operated by said light sensitive device for stopping said relative movement with said article in a predetermined position with respect tothe level oi liquid in said receptacle.

6. In apparatus for immersing an article -in av liquid, the combination of a liquid receptacle having a rliquid recirculating system for-main taining the 'liquid at a constant' level in said receptacla'with a support for said article,l means Afor moving said receptacle and supportrelative to each other to immerse the article, a light sensitive. device which is energized in response to relative movement of said article With respect thereto, and a timing device which is loperated 1120,11 .energzation of said light sensitive device, saidtiming device being operable a predetermined .time after operation thereof to stop said relative movement with said article in a Vpredetermined pgsition with respect to the level of liquid in s adrecentacle.

7. In apparatus for immersing an article ina liquid, the ,combination of a liquid receptacle hav ing a liquid recirculating system f or maintaining the liquid at a constant level in` said receptacle,

`with a support for said article, a, hydraulic. mo,- IVtorior elevating said receptacle to immerse the `article,an electrically operated valve forl stopa distance correspondingto the height ofsaid article for energizing said time delay circuit, said time: delay'circuit delaying operationl of said electrically operated valve until said article is im- 112 mersed to .a predetermined depth below-the `level of said liquid.

8; Ln apparatus for immersing an article-ina liquid, the combination of a liquid receptaclehaving va yliquid recirculating system for-:maintaining the liquid at aconstant'level .in said receptacle, with a support for said article, a hydraulic motor for elevatingpsaid receptacle `tuinimerse the. article, Va valve for `stopping theoperation of said motor,ia. lightsensitive,devicercarried by said receptacle which is maintaineddeenergized bysaidarticle during the initial movement,v of said receptacle to immerser said article and is energized Vwhen it is moved .out ofthe range of said article,` and means-responsivev to energiza-tion of saidlight sensitive device yforen-- erating said valve.

9. In .apparatus for immersing an article ln liquid, the combination of a, liquid: receptacle having a liquid recirculating system for maintaining the liquid .at a constant Alevel in'said :receptacle, with a support for said article, a, :hydraulic motor forelevating said receptacleto immerse the article, a valve forstopping lthe `operation oi said motor, a lightsensitive device carried-by said receptacle which is maintained deenergized by said article during the initial: movement of said tank to immerse said article-and is energized when it is moved out .of thelfrange of said article, ancla .timing device rendered operable upon energization of saidlight sensitive device for operating said valve a predetermined 4time after energiza-tion of said light sensitive device to stop said receptacle -in .a vposition varyingwith the size .of said article vand with said article immersed to a predetermined' depth with 4respect to the level of liquid in said receptacle.

10. In apparatus offthefcharacter described, the combination .comprising a receptacle .containing a liquid, a movable conveyor having article supports thereon, a control device responsive to move.- ment of each of said supports into an operative dipping positionwith respect tol said receptacle for stopping the movement lof' said conveyor, a Huid pressure motor for moving said receptacle toward andr away from said Yconveyor toV immerse articles .on said supports in said liquid, anlup control valve rendered roperative .upon operation oi vsaidv control device to .operatesaid motori'to move said-receptacle toward said conveyor `for immersing an article on ysaid support, alight sensitive devicecarried by said receptacle :which is maintained deenergized by said articleduringiinitial movement of saidreceptacle toward said` con- -veyor and is energized/.by relative movement of said article out rof the range thereof, circuit means responsive -to the electrical output ofsaid light sensitive device for operating said up. valve to stop the -movement ofsaid-receptaclie toward said conveyor, 4and `a down-Ycontrol'valve forroperating said motor tomove said receptacle. away from said conveyor.

11. In apparatus of the character described, the combination comprising a receptacle containing a liquid, a Vmovable conveyor having arti cle supports thereon, a controldevice responsive -tomovement of each of said supports into an operative dipping position `with respect to said receptacle for stopping the-movement of said conveyor, a fluid pressure motor for-moving said receptacle tov/ard' andaway from said:y conveyor to'immerse articles onsaid supports in said liquid, an up control valve rendered operative upon operation of said control device to operatesaid motor to movesaid receptacle toward said conment of said article out of the range thereof, a I' time delay device controlled by said light sensitive device, valve control apparatus controlled by said time delay device for operating said up valve t stop the movement of said receptacle towards said l conveyor, said time delay device affording a delay in operation of said up valve after energization of said light sensitive device to provide immersion of said article in said liquid to a predetermined depth, and a down control valve for operating said motor to move said receptacle away from said conveyor.

12. In apparatus for immersing an article in a liquid, the combination of, a stationary frame structure, a conveyor mounted for movement on said frame structure, said conveyor having supports thereon each for supporting an article, a receptacle containing a, liquid, means mounting said receptacle on said frame structure for movement towards and away from said conveyor for immersing and withdrawing articles from said liquid, motor means for moving said receptacle, a light sensitive device supported on said receptacle above the top thereof, a light source supported on said receptacle at a point thereon removed from said light source in a position above the top of said receptacle to illuminate said light sensitive device, an opaque shield mounted on said frame structure between said light sensitive device and said light source, the upper edge of said shield being higher than the bottom edge of an article supported on one of said supports, means operated by each of said supports upon movement thereof by said conveyor to a position in which the article on said support is over said receptacle for operating said motor means to move said receptacle towards said conveyor, said article shielding said light sensitive device from said light source, and permitting illumination of said light sensitive device by said light source g upon elevation of said light sensitive device and light source by said receptacle above the top of said article, and circuit means responsive to said light sensitive device for stopping said motor means 13. In apparatus for immersing an article in a liquid, the combination of, a stationary frame structure, a conveyor mounted for movement on said frame structure, said conveyor having supports thereon each for supporting an article, a receptacle containing a liquid, means mounting said receptacle on said frame structure for movement towards and away from said conveyor for immersing and withdrawing articles from said liquid, motor means for moving said receptacle, a light sensitive device supported on said receptacle above the top thereof, a light source supported on said receptacle at a point thereon removed from said light source in a position above the top of said receptacle to illuminate said light sensitive device, an opaque shield mounted on said frame structure between said light sensitive device and said light source, the upper edge of said shield being higher than the bottom edge of an article supported on one of said supports, means operated by each of said supports upon movement thereof by said conveyor to a position in which the article on said support is over said receptacle for operating said motor means to move said receptacle towards said conveyor, said article shielding said light sensitive device from said light source, and permitting illumination of said light sensitive device by said light source upon elevation of said light sensitive device and light source by said receptacle above the top of said article, an electrical time delay control device energized by said light sensitive device, said electrical time delay control device having an output which is delayed a predetermined time interval after energization thereof, and control means responsive to the output of said electrical time delay control device for stopping said motor means.

RUSSELL A. TARLTON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

